Earthquakes and extreme rainfall induce long term permeability enhancement of volcanic island hydrogeological systems.

ABSTRACT: Earthquakes affect near-surface permeability, however temporal permeability evolution quantification is challenging due to the scarcity of observations data. Using thirteen years of groundwater level observations, we highlight clear permeability variations induced by earthquakes in an aquifer and overlaying aquitard. Dynamic stresses, above a threshold value PGV > 0.5 cm s^-1, were mostly responsible for these variations. We develop a new model using earth tides responses of water levels between earthquakes. We demonstrate a clear permeability increase of the hydrogeological system, with the permeability of the aquifer increasing 20-fold and that of the aquitard 300-fold over 12 years, induced by fracture creation or fracture unclogging. In addition, we demonstrate unprecedented

SUBMITTER: Vittecoq B 

PROVIDER: S-EPMC7677319 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature